The present invention relates generally to cooling of electronic components in electronic devices. More particularly, the present invention relates to a heat sink structure which uses a cabinet of an electronic device.
As the art moves towards higher power integrated circuits and components, hereinafter referred to as heat emitting components, heat transfer from the heat emitting components becomes increasingly difficult and more important. One conventional technique to remove heat from a heat emitting component is to employ a finned heat sink which is placed in thermal contact with the heat emitting component. In this manner, heat generated by the heat emitting component is conducted to the heat sink and then dissipated to the ambient environment.
Hassanzadeh et al., U.S. Pat. No. 5,761,041, which is herein incorporated by reference in its entirety, teaches a finned heat sink which is placed in thermal contact with a heat emitting component. To mount the heat sink, a bolster plate is positioned below a printed circuit board, and two pins extend up from the bolster plate, through the printed circuit board and through the base of the heat sink. A spring, engaged with the two pins, presses the heat sink into thermal contact with the heat emitting component.
Although the heat sink of Hassanzadeh et al. is suitable for its intended purpose, in some applications, there is only limited space for the heat sink. In these applications, the size of the heat sink which can be placed in the limited space is not adequate to sufficiently cool the heat emitting component. To enhance heat transfer from the heat emitting component and heat sink in this event, additional and/or more powerful fans are often used. However, to avoid excess power consumption and to avoid exceeding noise level limits, the size of these additional and/or more powerful fans is severely restricted.
Accordingly, the art needs a method of enhancing heat transfer from a heat emitting component where there is only limited space for a heat sink and without providing additional and/or more powerful fans.
In accordance with the present invention, a heat sink structure includes a lower heat sink in thermal contact with a heat emitting component. The heat sink structure further includes an upper heat sink and at least one heat pipe extending from the lower heat sink to the upper heat sink. At least one spring urges the upper heat sink away from the lower heat sink and into thermal contact with a cabinet, sometimes called a cover or a lid, of a system such as a computer system.
During use, the heat emitting component generates heat. This heat is conducted to the lower heat sink which dissipates some of this heat to the ambient environment. Further, some of the heat is conducted from the lower heat sink to the upper heat sink through the at least one heat pipe. The upper heat sink also dissipates some of this heat to the ambient environment. At the same time, some of the heat from the upper heat sink is conducted to the cabinet.
Since the cabinet has a relatively large surface area and is exposed to the outside of the computer system which is relatively cool compared to the inside of the computer system, the cabinet is extremely effective at dissipating heat to the ambient environment, and in particular, to the outside of the computer system.
Recall that in the prior art, fans were utilized to remove heat from inside of the computer system. However, as the art moved to higher power components, the amount of heat which had to be remove from the computer system increased. This additional heat was removed by providing additional and/or more powerful fans. Disadvantageously, these additional and/or more powerful fans consumed more power which increased operating cost of the computer system. Further, these additional and/or more powerful fans resulted in an increase in noise which was detrimental to the performance of the computer system.
In contrast, a heat sink structure in accordance with the present invention removes heat from inside of a system such as a computer system directly through the cabinet and to the outside. Advantageously, this heat is removed without having to power a fan and without generating noise. Accordingly, the prior art requirement of providing additional and/or more powerful fans is eliminated.
Further, since the heat sink structure utilizes the cabinet to enhance heat dissipation from the heat emitting component, the heat sink structure is well-suited for use when only a limited amount of space is available for the heat sink, i.e., when the distance between the heat emitting component and the cabinet is relatively small.
Also in accordance with the present invention, a method includes pressing a lower heat sink into thermal contact with a heat emitting component. An upper heat sink is supported above the lower heat sink, the lower heat sink being a thermally connected to the upper heat sink. The method further includes pressing the upper heat sink against a cabinet.
These and other features and advantages of the present invention will be more readily apparent from the detailed description set forth below taken in conjunction with the accompanying drawings.